Thousands of childcare workers are walking off the job to push for higher wages, but the federal education minister says he doesn't decide pay rates. About 7000 early childhood workers went on strike on Wednesday afternoon to hold rallies across the country, causing 350 centres to close. It's the fourth walk-off from the sector in 18 months. "It's outrageous that Australia's qualified early childhood educators are earning $22 an hour," Helen Gibbons, from the early childhood union United Voice, said in a statement. Ms Gibbons says the pay rate is not reflective of early childcare workers upskilling to meet higher national qualification standards. United Voice expects the strike to affect up to 40,000 parents, and says it's put the government on notice. Education Minister Dan Tehan says the government does not set pay rates for any industry in the private sector. "The federal government does not own or run child care centres and does not set pay rates in the industry," he told AAP on Wednesday. The Fair Work Commission in February dismissed early childhood union United Voice's case calling for equal pay. A separate case has been made to the commission by the Independent Education Union of Australia over early childhood teacher wages, with a decision expected later this year. Treasurer Josh Frydenberg says the government has invested record amounts in the sector and it will flow on to workers. "That will create a more sustainable childcare sector, a bigger and better childcare sector, and that's good for the employees as well," he told reporters in Canberra. The federal government recently introduced an uncapped childcare rebate system, in which households with an annual income under $186,958 will no longer face a cap on the rebate paid each year. Both parents must be working, studying, volunteering or searching for work at least eight hours a fortnight to be eligible. "We can no longer treat childcare as just a child-minding service so that mum and dad can go to work," Labor leader Bill Shorten told reporters. "What we need to do is treat it as education, and if we're going to treat it as education we need to pay the workforce better." ACTU president Michele O'Neil said the government doesn't value childcare workers. "It's because 96 per cent of you are women that your pay is as low as it is ... So we are going to fight to make equal pay an election issue," she told a rally in Sydney. Australian Associated Press